Does soil filled with nitrogen increase the weight of worms compared with soil without nitrogen? The weight of 20 randomly selected worms is acquired, 10 in soil with nitrogen and 10 in soil without nitrogen. The mean weight of worms in soil with nitrogen was 36.6 micrograms whereas the mean weight of worms in soil without nitrogen was 27.3 micrograms. A researcher randomized the data over 100 trials, and the difference of means for each trial is shown in the dot plot below.